树形咋样做？

Question

在asp.net中想做一个像论坛左栏一样的树形结构，咋做?数据村数据库读出。

Answer 1

Ajax Tree:
http://blog.csdn.net/ChengKing/archive/2006/08/27/1128545.aspx

Answer 2

asp.net 1.1 要下载树控件，2.0有现成的treeview,这个论坛好像用的是类是梅花雪的树形控件，如果是2.0的treeview,在msdn中又从数据库读数据的例子，我自己的一个，感觉很垃圾：
protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            ddlbll mybll = new ddlbll();
            DataTable mytab = mybll.GetKemu();
            foreach (DataRow row in mytab.Rows)
            {
                TreeNode mynode = new TreeNode();
                mynode.Text = row["KeMuName"].ToString();
                mynode.Value = row["KeMuId"].ToString();
                mynode.PopulateOnDemand = true;
                mynode.NavigateUrl = "";
                //mynode.SelectAction = TreeNodeSelectAction.Expand;
                TreeView1.Nodes.Add(mynode);
            }
            
        }
    }
    protected void selectednodechang(object sender, EventArgs e)
    {
        TreeNode mynode = TreeView1.SelectedNode;
        switch (mynode.Depth)
        {
            case 0:
                populatejiaocai(mynode);
                break;
            case 1:
                populateketi(mynode);
                break;
            case 2:
                navigatenode(mynode);
                break;
        }
    }
    protected void populatejiaocai(TreeNode node)
    {
        ddlbll mybll = new ddlbll();
        DataTable mytab = mybll.GetJiaocai(Convert.ToInt32(node.Value));
        if (mytab.Rows.Count > 0)
        {
            foreach (DataRow row in mytab.Rows)
            {
                TreeNode mynode = new TreeNode();
                mynode.Text = row["JiaoCaiName"].ToString();
                mynode.Value = row["JiaoCaiId"].ToString();
                //mynode.PopulateOnDemand = true;
                mynode.NavigateUrl = "";
                node.ChildNodes.Add(mynode);
            }
            
        }
    }
    protected void populateketi(TreeNode node)
    {
        ddlbll mybll = new ddlbll();
        DataTable mytab = mybll.GetKeti(Convert.ToInt32(node.Value));
        if (mytab.Rows.Count > 0)
        {
            foreach (DataRow row in mytab.Rows)
            {
                TreeNode mynode = new TreeNode();
                mynode.Text = row["KeTiName"].ToString();
                mynode.Value = row["KeTiId"].ToString();
                mynode.NavigateUrl = "~/school/keti.aspx?kid=" + mynode.Value;
                mynode.Target = "mainFrame";
                
                node.ChildNodes.Add(mynode);
            }
            node.Expand();
        }
    }
    protected void navigatenode(TreeNode node)
    { 
    
    }
}

Answer 3

private void Tree()
{
//数型控件的运用步骤
TreeNode treenode=new TreeNode();
treenode.Expanded=false;
TreeNodeCollection tree_coec=new TreeNodeCollection();
TreeView1.Nodes.Clear();
treenode.ID="nodes"; treenode.Text="<font size=2>xxxx</font>";
treenode.ImageUrl = "images/treeimage/root.gif";
treenode.ExpandedImageUrl = "images/treeimage/root.gif";
treenode.NavigateUrl="Xsht.aspx?classid=-1";
TreeView1.Nodes.Add(treenode);
tree_coec=TreeView1.Nodes;
creattree(tree_coec[tree_coec.Count - 1].Nodes, -1);
} private void creattree(TreeNodeCollection nds,int id)
{
SqlDataReader ds=ad.method_1("select_class",id);
while(ds.Read())
{
TreeNode treenode_p=new TreeNode();
TreeNodeCollection tree_coec_p=new TreeNodeCollection();
treenode_p.Text="<font size=2>" +ds["name"]+ "</font>";
treenode_p.ImageUrl = "images/treeimage/folder.gif";
treenode_p.ExpandedImageUrl = "images/treeimage/folderopen.gif";
treenode_p.NavigateUrl = "Xsht.aspx?classid="+ ds["classid"];
nds.Add(treenode_p);
creattree(nds[nds.Count - 1].Nodes, Int32.Parse(ds["classid"].ToString()));
}
ds.Close();
}